Vacuum relief device for internal combustion motors



P 29, 1954 c. P. HEBBARD 3,150,649

VACUUM RELIEF DEVICE FOR INTERNAL COMBUSTION MOTORS Filed Oct. 5, 1962 2Sheets-Sheet 1 l/ I I I. I m

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VACUUM RELIEF DEVICE FOR INTERNAL COMBUSTION MOTORS Filed Oct. 5, 1962 2Sheets-Sheet 2 fay/2Z by 1 Wm United States Patent f 3,150,649 VACUUMRELIEF DEVICE FOR INTERNAL COMBUSTION MOTORS Carl P. Hebbard, Lexington,Mass, assignor, by mesne assignments, to Herman S. Swartz and Carl P.Hehhard, doing business as Equipment Research Company, Lexington, Mass,a co-partnership Filed Oct. 5, 1962, Ser. No. 228,633 13 Claims. (Cl.123-97) This invention relates to a device for operating automaticallyto relieve excess vacuum in the intake manifold of an internalcombustion motor under certain conditions of operation. For example,when an automobile is traveling along a road and the foot on theaccelerator pedal is lifted to reduce the opening of the carburetorvalve, the car drives the motor, causing the cylinders to act as pumpsto draw air from the intake manifold faster that it can be suppliedthrough the partly closed carburetor valve. This increases vacuum in themanifold and sucks undesired fuel from the carburetor, such fuel beingwasted, some of it usually condensing on the walls of the intakemanifold. Various devices have been made for the purpose of relievingexcess vacuum thus caused, but for practical operation of an automobile,other conditions of operation must be taken into account. It is anobject of the present invention to provide an air inlet for the intakemanifold, the inlet containing a control valve responding automaticallyto the following conditions of operation, the valve being normallyclosed, especially when the motor is being accelerated.

(1) When the car is traveling with the accelerator pedal depressed toany position and the pedal is lifted any amount, the valve opens inaccordance with the amount of lift.

(2) When the car is at rest or traveling less than about mph and thethrottle is closed to idling position, the valve is closed (to preventstalling).

(3) When the car is traveling at a greater speed than about m.p.h. withthe throttle closed to idling position, as when decelerating or runningdownhill, the valve is open.

(4) If the car has vacuum-actuated brakes, application of the brakescloses the valve regardless of other conditions of operation if thevalve is then open.

By supplying the inlet from the crank-case and the valve chamber at thetop of the motor, vapors in these chambers can be drawn off to keep thechambers well ventilated and also to supply dust-free air to the intakemanifold. This extra air not only reduces the vacuum in the intakemanifold and the fuel sucked in, but also sweeps through the manifold toprevent condensation of fuel on the walls thereof.

These and other desirable objectives are attained by the combination andarrangement of parts hereinafter described in detail and illustrated onthe drawings, of which FIGURE 1 is a side elevation of an internalcombustion motor on which is mounted a device embodying the invention;

FIGURE 2 is a side elevation, on a larger scale, of the device itself;

FIGURE 3 is a plan view of the same;

FIGURES 4 and 5 are sections on the lines 44 and 5-5 of FIGURE 3; and

FIGURES 6, 7, 8 and 9 are partial side elevations of the device, on asmaller scale, showing different positions of the moving parts.

A conventional illustration of the power plant of an automotive vehicleis given in FIGURE 1 of the drawings. This comprises a multi-cylinder,internal combustion motor 10 with the customary carburetor 12communicating with an intake manifold 14. A butterfly valve (not shown)3,150,649 Patented Sept. 29,, 1964 in the manifold is the throttle whichis connected by a suitable linkage 16 to the accelerator pedal 18. Themotor 10 has a fan 20 which is driven through a belt 22 which connectsit to the main shaft of the motor. A brake pedal 24 is connected by alever 26 and rod 28 to a brakeapplying mechanism (not shown) which maybe vacuumoperated.

Mounted on the motor 10 at a suitable and convenient location is amechanism 30 which embodies the present invention. As shown, themechanism 30 has a frame 32 consisting chiefly of a pair of parallelplates between which an arcuate rack 34 is mounted to rock about itscenter as an axis. The teeth 36 of the rack may be conventional or, asshown, may consist of the coils of a helical spring secured to anarcuate strip. The rack 34 is connected by a rod 38 to thethrottle-operating linkage 16 so that when the accelerator pedal 18 ispressed to open the throttle, the rack 34 rocks in the clockwisedirection to the position shown in FIGURE 2. The moving parts of thedevice are usually in the position shown in FIGURE 2 when the motor isimpelling the vehicle. When the operators foot lets up on theaccelerator pedal 18, the rack 34 rocks in the counterclockwisedirection (FIGURE 6). The rack 34 has a hub portion 40 which is fittedon a fixed bushing 42 extending between the plates of the frame 32 (FIG-URE 4). Iournalled in the bushing 42 is the tubular stem 44 of an airvalve 46 which consists of an outer cylindrical cup-shaped member 48 andan inner cylindrical cupshaped member 50 telescoped into the outermember to form a valve chamber 52. The outer valve member 48 has one ormore holes 54 through its side wall, two such holes being indicated inFIGURE 4. The inner valve member 50 has one or more holes 56 through itsside wall which are movable into and out of registry with the holes 54by relative rotative movements of the members 48, 50 to open and closethe valve. In the embodiment of the invention illustrated, the outervalve member 48 is stationary, the inner member 50 being rotatable. Thestem portion 44 of the inner member 50 is journalled in the bushing 42for that purpose. The holes 54 in the wall of the outer valve member 48are preferably diametrically opposed and communicate with pipes 58, 60respectively. The pipes lead to any desired sources of air. By runningone of them to the valve chamber 62 at the top of the motor, and theother to the crankcase 64 at the bottom of the motor, these parts of themotor can be ventilated and can provide dust-free air for the intakemanifold. A third pipe 66 serves as an air duct to the intake manifold14 and communicates with the valve chamber 52 at any convenient pointsuch as a hole 68 through the bottom of the cup-shaped valve member 48.Since the pressure in the intake manifold is always lower thanatmospheric during the operation of the motor, more or less suction ismaintained in the valve chamber 52 which is relieved by opening thevalve to admit air through the pipes 58, 60.

The tubular valve stem 44 extends through and beyond the bushing 42, thefurther end being closed by a screw-threaded plug 70. Mounted on thisprojecting end of the valve stem 44 is an arm 72 which carries a pin 74.The arm 72 is rockable to open the valve 46 when in the position shownin FIGURE 6, or to close the valve when in the position shown in FIGURE7. The inner and outer members of the valve 46 are yieldingly maintainedin assembled relation by a helical spring 76 one end of which is securedto the outer member 48, the other end being secured to the plug 70 inthe end of the stem 44. When the valve parts are being assembled theyare turned relatively so that the spring 76 will not only draw the valveparts toward each other but will also tend to turn the inner member 58clockwise to the closed valve position, the outer member 48 beingstationary. A suit- 3 able stop 78 is mounted on the frame 32 to beengaged by the arm 72 when the valve 46 is in its closed position.

For operation of the valve, a tongue or click 80 is mounted on a rockshaft 82 journalled in the frame plates 32. The click 8% is arranged toengage between successive teeth 36 of the rack 34 when it is in its midposition on the line of centers between the axes of its shaft 82 and ofthe rack 34. A spring 84 attached to one of the plates 32 and to a pin86 projecting from the shaft 82 tends to maintain the click 8%)yieldingly in its mid position from which it is rocked in one directionor the other by movements of the member 34 about its axis.

Mounted on the shaft 32 outside of the frame 32 is an arm 88 to the endof which an end of a latch member 9%] is pivotally attached. The latchmember has an elongated slot 92 therein with a notch 94 in the upperedge of the slot adapted to receive the pin 74 on the valve arm 72. Whenthe arm 88 is rocked clockwise and the pin 74 is in the notch 94, thelatch member 9%) will move longitudinally toward the left and will rockthe valve arm 72 to open the valve 46, as indicated in FIGURE 6. If thelatch member 9! is then rocked upward enough to clear the pin 74 fromthe notch Q4, the spring 76 will act at once to close the valve 46, asindicated in FIGURE 7. Longitudinal movements of the latch member 96 areproduced by movements of the rack 34 from any position it may happen tobe in. Thus, clockwise movements of the rack 34, which take place whenthe accelerator pedal is pushed down, rock the shaft 82 in the oppositedirection and shift the latch member 90 toward the right so that if thepin 74 is in the notch 94, the valve is moved towards its closedposition. Likewise, a small counterclockwise movement of the rack 34accompanying an easing of the accelerator pedal will rock the shaft 82in the opposite direction to open the air valve 46 if the pin 74 is inthe notch 94. Thus the primary function of the mechanism is ordinarilyto close the air valve when the accelerator is pushed down and to openthe air valve when the accelerator is let up from any position. Wheneverthe accelerator pedal is let up, that usually results in the vehicledriving the motor to some extent instead of being driven by the motor.

However, when the motor is idling, the air valve should be closed eventhough the motor is not pulling the vehicle, as otherwise the motor willstall. To prevent this, means are provided for temporarily disabling thevalve-opening linkage which includes the latch member 94 Such meansinclude an arm 96 pivoted on the bushing 42 and extending downwardoutside of one of the frame plates 32. For convenience a similar arm ispivotally mounted outside the other frame plate 32, the lower ends ofthe arms 96 being connected by a short rod 98. The rack 34 is providedat its lower end with a tail 100 which is adapted to catch under the rod98 and rock the arms 96 a little when the rack is moved to its limitingcounterclockwise position as the accelerator is released to its idlingposition. One of the arms 96 carries a pin 102 which rides in a cam slot104 in a bunter element 196 which when lifted sufiiciently will engagethe lower edge of the latch member 90 and raise it sufliciently torelease the pin 74 from the notch 94 if it is then in the notch. Whenthe accelerator pedal is thereafter depressed, the tail 100 of the rack34 moves away from the rod 98 and permits a tension spring 108 to rockthe arms 96 back to their normal position. This lowers the bunter 106below the latch member 90 which then bears on the pin 74 so that whenthe latch member is moved to the right as the accelerator is depressed,the pin 74 will enter the notch 94 and be ready to open the air valvewhen the accelerator pedal rises.

On the other hand, when the vehicle is running downhill or rapidlydecelerating with a closed throttle, it is desirable that the air valvebe kept open in spite of the throttle being closed to idling position.For this purpose, means are provided to render the disabling meansineffective under such circumstances. A vane 110 is hingedly mounted ata convenient point on the frame 32 so as to be in the air stream fromthe fan 20. A spring 112 is provided to press the vane yieldinglyagainst a stop 114 so that the vane presents a broad face to the airstream. If the stream is considerable in force as when the motor isturning at a speed equivalent to travel of the vehicle at, say, twentymiles per hour, the vane is swung rearward by the stream against theforce of the spring 112. Pivotally connected to the vane by a rod 116 isthe bunter 1% which is shifted rearward when the vane is swung by theair stream. The slot 104 in which the pin 192 rides is inclined so thatrearward movetent of the bunter lowers the bunter far enough, asindicated in FIGURE 8, to keep it from engaging the latch member if thehunter is raised by the tail rocking the arms 96.

If the vehicle is equipped with vacuum-operated brakes, the vacuum inthe intake manifold must be maintained when the brakes are applied,regardless of the current operating condition of the motor. In such casethe brake pedal 24 is connected by a rod 122 to the cross rod 98 of thearms 96 in such a way that when the brakes are applied, the rod 122 isretracted enough (FIGURE 9) to rock the arms 96 to raise the bunter 106higher than it is raised by the action of the tail M0 so that even ifthe vane has lowered the bunter 136, that lowering is more than offsetby the elevating action of the brake rod 122.

The hereinbefore described mechanism for operating a valve is capable ofother useful applications. For example, if the connecting rod 38 isattached to the accelerator pedal in such a way that it moves toward theleft (FIGURE 2) when the accelerator pedal is depressed, and if thevalve 46 is in a fuel line running to the carburetor, any depression ofthe accelerator pedal at any position will supply extra fuel to thecarburetor.

I claim:

1. In combination, a valve and means for controlling said valve, saidmeans comprising a rack with a series of teeth movable in a path alongits length, a rockably mounted click comprising a straight tongueadapted to extend from its rocking axis into the space between thenearest two teeth of said rack when in its midposition, said click beingrockable from its midposition by movement of said rack in eitherdirection along its path, spring means tending to hold said click in itsmidposition, and connecting linkage responsive to rocking movements ofsaid click to open and close said valve.

2. Mechanism as described in claim 1, said rack being arcuate andmovable about the center of its arc.

3. Mechanism as described in claim 1, the teeth of said rack consistingof a helical spring secured at both ends.

4. Mechanism as described in claim 1, said connecting linkage comprisinga shaft on which said click is mounted, a crank arm mounted on saidshaft, a latch member attached to said crank arm, and means responsiveto longitudinal movements of said latch member to open and close saidvalve.

5. Mechanism as described in claim 4, said latch member having anelongated slot therein with a notch in a side edge of the slot, saidlatch-responsive means comprising a valve stem rockable to open andclose said valve, an arm fixed on said stem and a pin on said armadapted to engage in said notch to rock said arm and stem when the latchmember moves longitudinally.

6. Mechanism as described in claim 5, spring means tending to rock saidstem to the closed valve position, and auxiliary means operable to rocksaid latch member about its pivot attachment to said crank arm torelease said pin from said notch.

7. In an automotive vehicle having an internal combustion motor with anintake manifold and a throttle movable between an idling position and afull power position; an air duct opening into said intake manifold, avalve in said air duct, and means responsive to opening and closingmovements of said throttle from any position thereof for closing andopening said control valve, said means including a rack with a series ofteeth movable back and forth in step with opening and closing movementsof said throttle, a rockably mounted click comprising a straight tongueadapted to extend from its rocking axis into the space between thenearest two teeth of said rack when in its midposition, said click beingrockable from its midposition in either direction by movements of saidrack, spring means tending to hold said click in its midposition, andlinkage operatively connecting said click and said valve.

8. Mechanism as described in claim 7, said rack being arcuate andmovable about the center of its arc.

9. Mechanism as described in claim 7, said linkage comprising a shaft onwhich said click is mounted, a crank arm mounted on said shaft, a latchmember attached to said arm, and means responsive to longitudinalmovements of said latch member to open and close said valve.

10. Mechanism as described in claim 9, said latch member having anelongated slot therein with a notch in the upper side edge of the slot,said latch-responsive means comprising a valve stem rockable to open andclose said Valve, an arm fixed on said stem, a pin on said arm extendinginto said slot and adapted to engage in said notch, whereby longitudinalmovements of said latch member result in rocking movements of said valvestem when said pin is in said notch.

11. Mechanism as described in claim 10, and means operable to push saidlatch member upward to release said pin from said notch, and springmeans tending to close said valve.

12. In an automotive vehicle having an internal combustion motor with anintake manifold, a motor-driven fan, a throttle movable between anidling position and a full power position, and throttle operating means;an air duct opening into said manifold, a. valve in said air duct, aspring tending to maintain said valve closed, means responsive toclosing movements of said throttle to open said air Valve, saidresponsive means comprising a mechanical linkage between the throttleoperating means and the air valve, means actuated by said throttleoperating means when the throttle reaches its idling position to disablesaid linkage, and means responsive to a substantial air stream from saidfan to render said disabling means ineffective while the air stream issubstantial.

13. Mechanism as described in claim 12, said means responsive to the airstream from the fan including a vane rockably mounted near said fan, aspring tending to rock said vane toward said fan to an active position,said vane being movable by a substantial air stream away from said fanto an inactive position.

References Cited in the file of this patent UNITED STATES PATENTS1,319,755 Cherry Oct. 28, 1919 1,702,982 Schroder Feb. 19, 19292,036,205 Ericson Apr. 7, 1936 2,217,813 Post Oct. 15, 1940 2,506,511Mallory May 2, 1950 2,507,415 Mallory May 9, 1950 2,733,696 SchneiderFeb. 7, 1956 2,857,897 Vanderpoel et al Oct. 28, 1958 2,933,075 GeifroyApr. 19, 1960

7. IN AN AUTOMOTIVE VEHICLE HAVING AN INTERNAL COMBUSTION MOTOR WITH ANINTAKE MANIFOLD AND A THROTTLE MOVABLE BETWEEN AN IDLING POSITION AND AFULL POWER POSITION; AN AIR DUCT OPENING INTO SAID INTAKE MANIFOLD, AVALVE IN SAID AIR DUCT, AND MEANS RESPONSIVE TO OPENING AND CLOSINGMOVEMENTS OF SAID THROTTLE FROM ANY POSITION THEREOF FOR CLOSING ANDOPENING SAID CONTROL VALVE, SAID MEANS INCLUDING A RACK WITH A SERIES OFTEETH MOVABLE BACK AND FORTH IN STEP WITH OPENING AND CLOSING MOVEMENTSOF SAID THROTTLE, A ROCKABLY MOUNTED CLICK COMPRISING A STRAIGHT TONGUEADAPTED TO EXTEND FROM ITS ROCKING AXIS INTO THE SPACE BETWEEN THENEAREST TWO TEETH OF SAID RACK WHEN IN ITS MIDPOSITION, SAID CLICK BEINGROCKABLE FROM ITS MIDPOSITION IN EITHER DIRECTION BY MOVEMENTS OF SAIDRACK, SPRING MEANS TENDING TO HOLD SAID CLICK IN ITS MIDPOSITION, ANDLINKAGE OPERATIVELY CONNECTING SAID CLICK AND SAID VALVE.